Zhu Ling[a] (Chinese: 朱令; pinyin: Zhū Lìng, 24 April 1973 – 22 December 2023) was a university student who was best known as the victim of an unsolved 1995 thallium poisoning case in Beijing, China.
Her symptoms were posted to the Internet via a Usenet newsgroup by her friend from Peking University, Bei Zhicheng, and were subsequently proven to be caused by thallium poisoning.
Internet discussion of the crime has continued since then and became a hot topic on major online Chinese communities very frequently as a high-profile cold case.
After being attended to by Professor Li Shunwei (李舜伟), he informed Zhu Ling's mother that her condition was "very similar to a case of thallium poisoning at Tsinghua University in the 1960s.
In the medical records for that day, Professor Li Shunwei described Zhu Ling's condition as follows: "(the patient is) mentally clear and articulate, experiencing significant hair loss, limbs hurt by touching, redness at the fingertips and soles which are not swollen but with elevated temperature.
Highly suspicious of heavy metal poisoning, such as thallium and beryllium, consulted with Director Zhang Shoulin and professors including Ding Maobai".
On the same day, after a comprehensive neurology discussion, the diagnosis was revised to acute disseminated encephalomyelitis (ADEM), and treatment involved plasma exchange therapy.
Afterwards, Zhu Ling's parents spoke with some of the experts and learned that during the consultation at PUMCH, they considered that since thallium poisoning had been ruled out, they had to explore other potential causes from different perspectives.
Responses began pouring in within a matter of hours,[16] and news reports hailed the event as a milestone in remote diagnosis by Internet, especially in the People's Republic of China.
Of the more than 1,500 responses which Zhu Ling's friends received, roughly one-third proposed that she was suffering from thallium poisoning, the common antidote for which is Prussian blue.
In 1996, Dr. Li Xin and his colleagues published a paper detailing the construction and operation of the remote medical diagnosis system during the Zhu Ling's thallium poisoning incident, highlighting its significant role.
Bei Zhicheng, Cai Quanqing, and others at Peking University uploaded Zhu Ling's case information, including photos at the onset of the illness, laboratory results, neurological examination findings, and radiographic images (chest X-rays, brain MRI, etc.).
Dr. Li Xin and his colleagues at the UCLA School of Medicine set up servers to store Zhu Ling's medical data, collating and categorizing emails received from around the world.
According to the diagnostic and treatment logs at UCLA, as early as April 10, the day Bei Zhicheng sent the email, there were doctors responding with a diagnosis of thallium poisoning.
Doctors from St. Jude Children's Research Hospital pointed out in their response, "Suspected Thallium poisoning can be nearly diagnosed based on symptoms such as hair loss, gastrointestinal problems, and neurological issues".
Dr. Fink recalled that as Zhu Ling's condition worsened, they urged PUMCH through various channels to conduct thallium poisoning screening for a quicker and more accurate diagnosis.
Many years later, when Bei Zhicheng had a heated online debate with Sun Wei in 2005 on Tianya BBS, he wrote, "The former director of the ICU at Peking Union Medical College Hospital refused to conduct further tests for heavy metal poisoning.
On the other hand, Bei and his friends at Peking University attempted to provide PUMCH with a modem, hoping to facilitate direct communication with overseas medical professionals.
Dr. Aldis expressed deep regret at the limited communication channels between overseas doctors and PUMCH at that time, which hindered the exchange of information regarding Zhu Ling's diagnosis and treatment.
After multiple attempts of communication between Dr. Ivan Petrželka in Los Angeles Poison Control Center, Dr. Ashok Jain, Dr John Aldis and many other medial experts, PUMCH finally started treatment with Prussian blue on May 3, 1995.
In 2006, Wang Bu (王补), a veteran police officer with decades of experience in solving cases, inferred, "The scope of suspects is very small," and further speculated based on the strict management of Tsinghua University's female dormitories that "the perpetrator must be someone close to Zhu Ling".
Wang Bu was once hailed as the "pioneer of lie detection in the Chinese police force," and according to Zhu Ling's father, he was the director of the Research Department of the Public Security Bureau in Beijing.
In late 1995, the head of the Tsinghua University Police Station, Li Mucheng (李慕成), informed Zhu Ling's parents that there was a suspect, and after obtaining approval from higher authorities, they began to make progress, but details were kept confidential.
In February 1996, leaders of the Beijing Municipal Public Security Bureau's fourteenth department informed Zhu Ling's family that the case was challenging, and efforts were ongoing.
On Feb 27, 1996, Section 14 of Beijing Public Security Bureau told Zhu's parents "the case is difficult to resolve and they are working hard on it".
As a result, university employees packed up Zhu's belongings (including a camera, a watch, honey, coffee, and a lunch box) and stored them in the Chemistry department.
On Mar 25 and May 20 of 1997, Zhu Ling's family wrote petition letters to Beijing Public Security Bureau and the Party leaders, urging the resolution of the case.
[19] On April 2, 1997, The Beijing Public Security Bureau's Section 14 brought Sun Wei in for questioning, citing the reason as a "simple understanding of the situation, just changing the location".
Internet discussion of the crime has continued since then, and has frequently become a hot topic on major online Chinese communities as a high-profile unsolved case.
An online White House Petition on the whitehouse.gov website was created on 3 May 2013, demanding investigation of the major suspect who was believed to be living in the United States at the time.